The ruling could prompt police to reexamine rules and practices for the temporarily debilitating weapons.

Police used excessive force when they fired Tasers at a pregnant woman in Seattle and a victim of domestic abuse in Maui, a federal appeals court ruled Monday in a case that could influence how police handle those resisting arrest across the West.

The ruling by the U.S. 9th Circuit Court of Appeals, sitting in a full 11-judge forum used to decide important questions of law, could prompt police forces to reexamine their rules and practices for the temporarily debilitating stun guns.

In the Seattle case, a seven-months pregnant Malaika Brooks was driving her son to school when she was stopped by police, ticketed for driving 12 miles over the 20-mph speed limit and blasted with a stun gun three times after refusing to sign the citation.

Two years later and thousands of miles away in Maui, Jayzel Mattos was trying to defuse a brewing clash between her drunk husband and four police officers called to a domestic disturbance when one of the officers suddenly dropped her to the floor with two jolts from his Taser, which was set in dart mode.

The federal appeals court ruled that in both instances, police used excessive force and that their actions violated the Constitution's protection from unreasonable force.

While deeming the use of the stun guns in Seattle and Maui excessive, the court said the officers weren't liable in the civil suits filed against them because the law governing Taser use wasn't clearly established at the time of Brooks' 2004 arrest or when Mattos was jolted without warning for what police said was obstructing police at her home in 2006.

But the court's ruling Monday may now serve to establish that using stun guns without an imminent threat of harm is unreasonable, at least in some cases, exposing police officers to liability in future lawsuits, legal analysts said.

Barry McDonald, a constitutional law professor at Pepperdine University, said the 9th Circuit ruling wouldn't be unduly restrictive for law enforcement because the circumstances in the two cases it reviewed were unusual and unlikely to be relevant in most instances when police decide to use stun guns.

"They took some pretty sympathetic factual scenarios to establish this law," said Laurie Levenson, a criminal law professor at Loyola Law School, noting Brooks' advanced pregnancy and the allegedly unprovoked stunning of Mattos.

The ruling should encourage police to better assess the threat level they confront and the severity of the offense for which a citizen is resisting arrest, said Levenson, describing the decision as "certainly not a case where the court says police can't use Tasers."

The Los Angeles Police Department has detailed guidelines for officers on the appropriate use of stun guns and their procedures already comply with the court ruling, said Assistant Chief Sandy Jo MacArthur.

Other regional law enforcement agencies have been refining their stun gun rules after a similar decision last year involving Coronado police in San Diego County.

Monday's ruling could influence the outcome of a lawsuit filed by the parents of a San Bernardino man who died in May. Three officers were accused of shocking him repeatedly with stun guns for 10 minutes. Allen Kephart, 43, was stopped by three sheriff's deputies after he honked his horn at them for turning in front of his car, the lawsuit contends.

Four of the 11 judges dissented in part from the 9th Circuit ruling, including Chief Judge Alex Kozinski, who expressed concern that restricting the use of non-lethal force with Tasers could result in police resorting to more dangerous means to subdue those resisting arrest.

In the last decade, Kozinski said, half a million police officers were assaulted in the line of duty and 536 were killed, "the vast majority while performing routine law enforcement tasks like conducting traffic stops and responding to domestic disturbance calls."

Two of the dissenters disagreed that Brooks' constitutional rights were violated, saying she brought the action on herself by repeatedly refusing to sign the traffic citation or to get out of her car when police tried to arrest her.

"There are only so many ways that a person can be extracted from a vehicle against her will, and none of them is pretty. Fists, batons, choke holds, dogs, tear gas, and chemical spray all carry their own risks to suspects and officers alike," wrote Judges Barry G. Silverman and Richard R. Clifton.